Apparatus for low pressure permanent mold casting



June 15, 1965 F. H. LE JEUNE 3,188,703

APPARATUS FOR LOW PRESSURE PERMANENT MOLD CASTING Filed Aug. 8, 1962 SSheets-Sheet 1 A BY Q EL

June 15, 1965 F. H. LE JEUNE APPARATUS FOR LOW PRESSURE PERMANENT MOLDCASTING 3 Sheets-Sheet 2 Filed Aug. 8, 1962 June 15, 1965 F. H. LE JEUNE3,188,703

APPARATUS FOR LOW PRESSURE PERMANENT MOLD CASTING Filed Aug. 8, 1962 3Sheets-Sheet 3 I I. J,

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I i 1 la /1//r/ //4 V/ A77 IN\UHVT(HL )7 471/? Ac 7321716.

- 1 1 l I l I United States Patent 3,188,703 APPARATUS FOR LOW PRESSUREPERMANENT MGLD CASTING Frank H. Le Jeune, Jackson, Mich, assignor toKelsey- Hayes Company, Romulus, Mich, a corporation of Delaware FiledAug. 8, 1962, Ser. No. 215,604 8 Claims. (Cl. 22-77) This inventionrelates to apparatus for casting metals by the low pressure process andparticularly to an index machine supporting a plurality of permanentmolds in which metal is cast by the low pressure process.

It is an object of the present invention to provide apparatus forcasting metal in permanent molds by the low pressure process atrelatively high production rates.

It is another object of the present invention to provide an indexmolding machine supporting a plurality of paired crucibles and molds,wherein means are provided for successively filling the crucibles,pneumatically sealing the furnaces in which the crucibles are located,feeding metal from the crucibles into the molds by air pressure andremoving the cast parts from the molds.

It is another object of the present invention to provide apparatus ofthe above character having means for conveniently opening up thefurnaces in which the crucibles are located for the purpose ofperforming maintenance on the crucibles or the heating elements Withinthe furnaces.

It is still another object of the present invention to provide a machineof the above character in which the molten metal within the cruciblesand the stalks leading from the crucibles to the molds is kept in amolten condition and at a relatively constant temperature and in whichscum and other contaminant matter floating on the surface of the metalin the crucibles is not introduced into the molds.

It is still another object of the present invention to provide apparatusof the above character which is of rugged, sturdy construction, whichmay be relatively inexpensively fabricated for the volume of itsproductive capacity and which may be used for the mass production ofcastings by 1 the low pressure permanent mold system in a highlyconvenient and inexpensive manner.

These and other objects of the present invention will become apparentfrom the following detailed description taken in conjunction with theaccompanying drawings, wherein:

: FIGURE 1 is a perspective view, with parts broken away, of apparatusembodying the principles of the pres ent invention;

FIG. 2 is a reduced scale sectional view of the structure illustrated inFIG. 1, taken along the line 2-2 thereof;

FIG. 3 is an enlarged sectional view of the structure illustrated inFIG. 2, taken along the line 33 thereof; and

. FIG. 4 is a sectional view of a portion of the structure illustratedin FIG. 1, taken along the line 4-4 thereof.

Referring now to the drawings, the apparatus of the present inventionwill be seen to include a large circular table or platform having aplurality of depending legs 12 provided with rollers or Wheels 14 at theends thereof. The wheels 14 roll in a common circle over the surface ofa floor 16 as the table 10 is rotated about its central vertical axis.The legs 12 are spaced radially inwardly from the outer periphery 18 ofthe table, while braces 20 extend from the lower ends of the legs 12 tothe table 'outer periphery 18. A plurality of cross members 22interconnect the legs 12 to form the legs 12 and the table 14) into arigid unitized structure. A central column 24, connected to the table10, is journaled in the floor at its lower end to establish the axis ofrotation of the table 10. The table '10 includes a plurality ofangularly spaced radially extending beams 26 secured to the column 24 attheir inner ends. An annular supporting surface is formed on the table10 by a plurality of segmentally sector-shaped plates 28 resting on thebeams 26 in side-byside relation.

Each of the plates 28 defines a separate work station, as indicated at28a, 28b, 28c, 28d, 28e, 28 28g, 2811, 281', 28 28k and 28l. A pair ofcooperating mold halves 3i) and 32 are positioned at each of the workstations. The lower mold half is supported on the adjacent plate 28 withan annular insulating pad 34 disposed therebetween. The upper mold half32 is secured to a vertically movable plate 36 having a bracket 38 bywhich it is attached to a piston rod 40. The piston rod 40 of each Workstation extends from and is operated by a hydraulic cylinder 42. Aseparate cylinder 42 is provided for each work station and each cylinder42 is carried on a separate support member 44 fastened to the upper endsof three spaced vertical rods 46. The rods 46 pass through the plate 36and form ways for guiding the vertical travel of the plate 36, thusassuring the proper alignment of the upper mold half 3-2 with the lowermold half 30. The upper mold half 3-2 is thereby adapted to be raisedand lowered by its associated cylinder 42 for the purpose of opening thecavitydefined by the mold halves 30 and 32 to remove a part casttherein.

As may be seen in FIG. 3, a separate crucible 48 is supported beneatheach of the mold halves 30 adjacent the underside of the associatedplate 28. Each crucible 48 is supported by and enclosed within its ownthermally and pneumatically scalable enclosure or furnace, generallyindicated at 50. Depending from each of the bottom mold halves 30 is ahollow tubular stalk'52, which extends into the subjacent crucible 48.The interior of the upper end of the stalk 52 is tapered inwardly, asindicated at 54. The stalk end 54 is in direct communication with theinterior of its mold half 30 and particularly with a portion of the moldhalf 30 defining a sprue cavity 56. As may be seen in FIG. 3, a heatingcoil 58 is supported by the annular pad 34 in a position closely spacedaround the upper end of the stalk 52 to maintain metal within the stalkin a molten condition.

As further illustrated in FIG. 3, each of the furnaces includes a bottomwall member 60 and an annular enclosing side wall 62. The major portionof the side wall 62 is provided with a ceramic lining 64 for heatinsulating purposes. In addition, the lining 64 serves to supportheating coils 66. As is indicated in FIG. 3, each of the furnaces 50 hasan offset portion 68 which accommodates a spillway or mouth 70 of thecrucible 48. The spillway 7b is positioned immediately beneath an inletopening 72 formed in the adjacent plate 28. Thus, molten metal pouredthrough the opening 72 will fall onto the spillway 70 and run downwardlyinto the crucible 48. The height to which the crucible is normallyfilled is indicated by the line 74 and it will thus be seen that thislevel is substantially above the lower end of the stalk 52.

The crucible 48 is relatively fragile and must be properly supported.For this purpose, a base 75, resting on the bottom wall 60, supports thebottom of the crucible. In addition, a supporting member 76 supports thespillway 70 of the crucible. As may be seen in FIG. 3, an annularbracket 78 of angle iron material is welded to the outer surface of theenclosing side wall 62 and is bolted to the underside of the table 10.The annular furnace side wall 62 is formed with a metal bottom plate 86to which is secured a continuous seal 82 adapted to sealingly engage thefurnace bottom wall 60. An angle iron 8-4 is also welded around the sidewall adjacent the lower end thereof and is provided with several spacedbrackets 86, each of which pivotally supports a bolt 88 extendablethrough slots 90 in the furnace bottom wall 60. Nuts 92 and washers 94-are positioned on the ends of the bolts 88 ,to.

Patented June 15, 1965 engage the undersurface of the furnace bottomwall 60 so that, upon tightening of the nuts 92, the furnace bottom'Wall 50 will be drawn upwardly tightly against the seal 82. 7

Means for lowering the bottom wall 60 of a selected one of the furnaces50 is provided by a pair of spaced,

vertically extending jacks 96 adapted to engagethe underside of thebottom wall '60 of a furnace 59 disposed in vertical alignmenttherewith. The jacks 96 are provided with rack teeth 98, which mesh witha pair of pinions 99 supported for rotation'about a fixed axis byjournalblocks 109. The pinions 99 are co-rotatably associated with apair of pinions 102 adapted to be rotated by a rack lM which isreciprocable under the influence or" a power cylinder 1%. Thus, upon thehorizontal reciprocation of the rack 104, the jacks'96 are raised andlowered. By disengaging its bolts 88 from the slots 99, the bottomwallet) Hydraulic power supply units for operating the power cylinders42 are indicated generally at 142 as being mounted on the beams 26inwardly of the plates 28. Electricity for operating the furnaces may beintroduced from a suitablepower supply source .througha rotaryelectrical coupling (not shown) which may be positioned atthe upper endof the column 24. Similarly, compressed air may be admitted to therotary table 16 through a standard rotary coupling (not shown) alsosecured .to' the column 24. For sake of clarity, the hydraulic,pneumatic and electrical conduitsor-conductors have been omitted fromthe drawings. However, FIG. 3 showsa conduit 144 connected to eachfurnace, through which compressed air may be admitted to the interior ofthe furnace. A pressure relief .valve 145 is provided'as a safety.measure, protecting against the huild-upof excessive pressure in thefurnace.

of a given furnace may-be lowered by the jacks 96 for the I purpose ofcleaning. or replacing the crucible 48, repairin or' re lacin insulationmaterial, re airin or replac-,

ing a heating'elemennor performing any other desired maintenance. I

A valve mechanism, generally indicated at 163, is carriedby each of theplates 36 for closing the adjacent inlet opening 72 of itsassociatedfurnace Sill Thevalve mechanism 108 includes a guide tube lltldependingfrom the underside of itsplate 36 and a valve stem 112 slidablyextending through :the tube 110. A flange 114 is: j formed on the'lowerend of theitubelltliand is' engaged by one end ofa spring 116 whichbears at its other end against a valve element 118 secured to the lowerend of the valve stem 112. When aplate 36 is raisedby its cylinder 42,'a head 120 on the upper end of its valve'stenr 112 will engage. theupper surface of the plate 36to raise the valve element 118 away fromthe opening 72." When the plate 36 is again lowered, thespring 116 willurge the valve element 118' against the surface of the plate 28surrounding the opening 72 to seal the opening 72. In so doing, alost.rnotion relationship valve stem 112 and the tube 110.

Positioned adjacent the table 10 is a holding furnace 122, from whichmolten metal is fedthrough a pouring spout 124 into the crucibles 43. Amelting furnace 126 will occur between the is also desirably locatedadjacent the holding furnaceand is used for melting the particular alloybeing used. A conduit 128 is provided for the direct flow of metal fromthe meltingfurnace 126 to the holding furnace 122. The pouring spout 124of the holding furnace 122 is pivotally mounted, so that its pouring endmay be moved between a position immediately above the opening 72 of anadjacent work station and a retracted position clear of the table 10,permitting the table ltlto be indexed to a new position.

Means for indexing the table 10 is illustrated as comprising a largeGeneva gear 13% mounted on the column 24. The gear 130 has a pluralityof circumferentially spaced, radially extending slots or openings '132.-A rotary'drive plate 134 is provided with anrupstanding pin 136 adaptedto enter the slots 132 successively upon the rotation of the plate 134..The'spacing of the slots 132' and the circle of movement of the .pin136are such that the pin 136 will leave one slot 132 and enter the nextadjacent slot 132 during a given rotation thereof tdincrementally rotatethegear 130 and thus the'colurnn 24 The operation of the apparatus ofthe present invention 7 will :be largely apparent from the foregoingdescription of the apparatus. Such operation is repeated sequentially ateach work station. The plate v36 at a given work station is firstraised, both to raise the upper mold half 32 and to open :the opening 72of the furnace. The interior of j the mold is cleaned out and anyinserts required to be placed therein are inserted in the IIIlOld. Thus,in the production of brake drums, a cast iron-"brake liner may beinserted in the lower mold half 30 for the casting of the drum about theliner; At a succeeding station, the crucihis '48 isjfilled to thedesired level'by' the introduction of moltenmetal through the opening 72from the pouring spout 1-24 of the holding furnace 122. Next, thecylinder 42 of the workstation is operated to lower the plate 36,thereby closing the mold and sealing the furnace. The interior of thefurnace is then pressurized with compressed air admitted through theconduit 144. Various pressures maybe utilized but pressures between 7and 15 pounds per square inch are'normail. The pressurization of thefurnace is operable to cause molten metal within the crucible to flow upthe stalk 52 to theinteriorof the mold.

' As is well known in rhea-rt of low pressure casting, the

metal will solidify within the mold and any shrinkage resulting from thesolidification is takenup by the continued feeding under pressure ofmetal into the mold.

After the metal within the -mold has been permitted to solidify, the airpressure in its furnace is exhausted and the plate 36 is again raised.At the upper limits of its movement, ejector pins 11-48 dependingfromthe supporting members 44 may be. utilized toassist in the removal ofthe parts from the mold. 11f the construction of the mold is such thatthe cast :part 'will'li ft with the upper mold hat-M32, such ejectorpins .148 may be used to strike ejector plugs (not'shown) withinthe moldto eject the part from the mold. The mold islt hen. cleaned out andreadied for the time when it is next positioned adjacent the holdingfurnace '122. The operation is, of course, repeated in sequence at eachwork station. While one crucible is being refilled, molds at the otherwork stations are being filled through airpressure and the cast parts'are solidifying.

I-t*will be seen that the" apparatus of the presentinvem tion permits.the leaving of-a sizable heel of molten metal within each crucible 48 tostabilize the temperature wit-hi n. each furnace, yet each crucible isconsider-ably s'mal-lerland less expensive to fabricate, heat and main-'tain than crucibles which have heretofore been used in and table 10 towhich it is fixed. Thedrive plate 134 is driven in rotation bya motor138 through a gearreduction mechanism 140. There are twelve of the.slots 1321.

and each corresponds in angular position to one of the work stations28a, 28b, 28c, 28d, 28c, 281, 28g, 28h, 28L 28f, 28k and 28]. Thus, themotor 138 may be turned off during a period in which the pm 136 has leftone of the slots 132 and prior to its reentry into a'new slot 132 and,during this period, one of the work stations will be in a positionadjacent the holding furnace 122. In such p0sition, one of the workstations will also lie 'above'the jacks casting-by the low pressureprocess, Still, the'oxides or other contaminant matter=within eachcrucible 48 will float on the top of the metal within the crucible and,by'

virtue of the fact that the inlet of the stalk 52 is positionedbeheaththisleve-l, such contaminants-will not be introduced'into the interiorof the mold.

' While it will be apparent that the preferred embodiment hereinillustratedis well calculated to fulfillthe objects above stated,"itwill be appreciated that the-invention is susceptible to modification,variation and change without departing from the proper scope or fairmeaning of the subjoined claims.

What is claimed is:

1. Casting apparatus including a rotary table, a plurality of furnacescarried by said table in angularly spaced relation, a crucible in eachof said furnaces, a plurality of molds carried by said table in pairedrelation to said furnaces, means connecting each of said molds to thecrucible in the furnace to which it is paired, a stationary holdingfurnace, means for successively filling the furnaces on said table withmolten metal from said holding furnace as said table is indexed, andmeans for pressurizing said furnaces.

2. The structure set forth in claim 1 including a plurality of liftingmechanisms on said table disposed one above each of said molds, eachlifting mechanism 'being connected to an upper part of its adjacent moldfor openiug said molds to remove parts cast therein.

3. Casting apparatus including a rotary table, a plurality of furnacesdepending from said table in angularly spaced relation, a crucible ineach of said furnaces, a plurality of molds resting on said table andeach being arranged in a position directly above one of said furnaces,means connecting each mold to the crucible of the furnace directlybeneath it, means for pressurizing each of said furnaces, a stationaryholding furnace, means for successively filling the furnaces on saidtable with molten metal from said holding furnace as said table isindexed, and closable inlet means on each of said furnaces through whichmetal may be poured into said crucibles.

4. The structure set forth in claim 3 in which each of the furnaces onsaid table is provided with a bot-tom Wall on which its .crucible restsand including means for disengaging each of said bottom Walls from theremaining portion of said furnaces, and a stationary lowering mechanismadapted to support and lower the bottom wall of a furnace injuxtaposition thereto.

5. Casting apparatus including a rotary table, a pinrality of furnacescarried by said table, a cruciblein each of said furnaces, a pluralityof molds disposed on said table, each in a position above one of saidfurnaces, a stalk depending from each of said molds into the crucible ofits adjacent furnace, means for pressurizing each of said furnaces tocause molten metal within the crucible thereof to flow upwardly throughsaid stalks into the molds, and a stationary furnace adjacent theperiphery of said table for filling the crucibles of the furnaces onsaid table.

6. The structure set forth in claim 5 including a heating elementsurrounding each of said stalks, and a plurality of heating elements ineach of said furnaces to maintain metal in said stalks and saidcrucibles in .a molten condition.

7. Casting apparatus including a rotary table, a plurality of furnacescarried by said table and each having an inlet opening at its upper end,a crucible in each of said furnaces, a plurality of molds on said tabledisposed one above each of said furnaces and connected to the cruciblein its adjacent furnace, a separate lifting mechanism for each of saidmolds connected to an upper portion of one of said molds, valve meansassociated with each of said lifting mechanisms operable toautomatically close the inlet opening of its adjacent furnace upon thelowering of said upper mold portion, means for pressurizing each of saidfurnaces, and a stationary furnace adjacent the periphery of said tablefor successively filling the crucibles carried by said table.

8. The structure set forth in claim 5 including means for incrementallyadvancing said table in rotation to suc cessively move the furnacescarried by said table to a position adjacent said stationary furnace.

References Cited by the Examiner UNITED STATES PATENTS 1,913,945 6/ 33Morris et al 22-77 2,195,360 3/40 Daesen 2269 2,7 43,491 5/56 Berry22-77 2,912,728 1 1/59 Sylvester 22--69 MICHAEL V. BRINDISI, PrimaryExaminer.

1. CASTING APPARATUS INCLUDING A ROTARY TABLE, A PLURALITY OF FURNACESCARRIED BY SAID TABLE IN ANGULARLY SPACED RELATION, A CRUCIBLE IN EACHOF SAID FURNACES, A PLURALITY OF MOLDS CARRIED BY SAID TABLE IN PAIREDRELATION TO SAID FURNACES, MEANS CONNECTING EACH OF SAID MOLDS TO THECRUCIBLE IN THE FURNACE TO WHICH IT IS PAIRED, A STATIONARY HOLDINGFURNACE, MEANS FOR SUCCESSIVELY FILLING THE FURNACES ON SAID TABLE WITHMOLTEN METAL FROM SAID HOLDING FURNACE AS SAID TABLE IS INDEXED, ANDMEANS FOR PRESSURIZING SAID FURNACES.